Clinical benefits and bioequivalence of vortioxetine oral drop solution versus oral tablets

Background: Vortioxetine is efficacious and well tolerated in patients with major depressive disorder (MDD) and is available as an immediate-release tablet and oral drop solution. The oral drop solution may offer clinical benefits versus a tablet, such as the reduced risk of nausea, personalised dosing and ease of administration. Aims: To investigate the bioequivalence of vortioxetine 20 mg/mL oral drop solution versus a 20 mg immediate-release tablet. Methods: Healthy adults were randomised 1:1 to receive vortioxetine 20 mg oral drop solution or immediate-release 20 mg tablet after fasting on days 1 and 29 in an open-label, single-centre, single-dose crossover study. The area under the plasma concentration-time curve from 0 to 72 h (AUC0-72h) and maximum plasma concentration (Cmax) were analysed. Bioequivalence was concluded if the 90% CI for the oral drop solution-to-immediate-release tablet ratio for AUC0-72h and Cmax were contained within a range of 0.80-1.25. Results: Vortioxetine oral drop solution was bioequivalent to the tablet (n = 26; estimated AUC0-72h ratio 1.06 (90% CI: 1.03-1.10); Cmax ratio 1.01 (90% CI: 0.97-1.05)). A similar proportion of participants reported adverse events in each study arm but more headache events (7 vs 1) were reported with the oral drop solution versus tablet. The most common adverse event was nausea (16-23% of participants; all mild intensity). Conclusions: Vortioxetine oral drop solution is bioequivalent to immediate-release tablets. Oral drop solution provides an alternative to tablets and facilitates clinical benefit through individualised treatment, including gradual dose up-titration, for patients with MDD.